On November 20th at dawn, a start was made for LaPaz. We had decided that the trip should be cut into three almost equal stages. The first stop was to be at a small cove know as Los Frailles; the second at Ensenada de Los Muertos; and the third day we hoped to be make it close into La Paz or close into the vicinity of La Paz. As a matter of fact we did not wish to arrive there on Sunday, which would have been our third day, because the Mexican officials levy an out of hours toll on Sundays, holidays or any time that is not during their working hours. I believe it can be said that their working hours are very short and extend from 9:00 A.M. to 2:00 P.M.
We anticipated a most difficult trip up the Gulf of California. It is notorious fo it’s northerly winds that blow all of the time. Sometimes they blow with marked ferocity. In addition to the wind that blows directly against you and makes a choppy sea, there is a current that is set wouthward by the force of the wind, further impeding your progress.
__________________________________________
Musings in the past tense:
A couple of posts ago, I included a Google terrain map of the tip of the Baja Peninsula. La Paz is Northwest of Cabo, but on the Eastern Side of the Peninsula. So beating up the right coast in the Gulf of California to get to La Paz would have as Kimball would say:
“the character of work”
The next couple of posts should be interesting.
______________________________
Musings in the present tense:
In my first sail of 2009, we struggled with a lee helm.
I was writing an email from my phone, but I hit the wrong button and *poof*.
So I thought I’ll recreate it here, using all my fingers on the keyboard.
The Admiral had been out on New Year's day and her sailing partner for that day demonstrated tying off the tiller with the bitter end of the mainsheet to make the helm self tending.
She wanted to experiment with that technique some more. But with the lee helm it wasn't happening. We didn't want to lead the bitter end of the mainsheet to the leeward side, so a struggle to get it to work ensued. I tried to figure out what sail trim would move the Center of Effort back to balance the Center of Lateral Resistance and give us a couple of degrees to Windward Helm to work with.
I couldn't do it, and my head seemed to be hitting a brick wall. The wall seemed to be saying:
"You got a little jib, you dolt! There can't be enough force up there to be giving you Lee Helm!"
So today I turned back to the discussion of CE and CLR in Chapman - I don't have a photographic memory, but having read something I can sometimes find it again.
Chapman, on page 279, describes Lee Helm, and goes on to say:
“many sailboats develop a slight tendency for lee helm in light air”
Oh
Well that explains it I guess, but what to do about it?
The very nice explanation of the forces on the keel and rudder, and a great figure (8-04), showing why a slight weather helm generates the best lift, vs. drag situation was there as I remembered. But I could not find an explanation of sail trim that would turn a slight Lee Helm into a slight Weather Helm in light winds on one of the many sailboats that develop this tendency. Sail trim books seem to focus on sail trim, not sail and helm trim. I guess that makes a certain sense, but sailing is a balancing act, and the sails are only on one side of that fulcrum.
I'd been reading the Sail Trim book from SAIL magazine, and searched and searched, but couldn't find Lee Helm anywhere. Then, while driving, it hit me. In 'Trimming the Genoa for Speed' by Mike Toppa, there are a couple of statements:
"Most boats have different size Genoas for different wind speeds"
and
"the sail's maximum draft is about 45 percent of the total girth distance back from the luff."
I had rigged the J24 by myself while the sun was heading for the horizon. There were a couple of gusts that come over the point of the marina, so I decided to go for the softer side of sailing and hanked the 100% jib on the forestay.
45% back from the luff of the 100% is further forward than 45% back from the luff of the 150% Genoa. And if we were carrying the sails we should have for the wind conditions we were sailing in, then we would have set the 150. Headsail change at night while doublehanding a J24? Just to mess around with self tending the tiller?
Now why didn't I think of that?!
I was too busy listening to the music the waves were making on the hull.
We had sailed by 'D', the Flashing Green on the pole stuck in the mud. and decided to tack. 'E' was still on the dock at the Berkeley Yacht Club, so once we passed where it used to be, we headed north.
A discussion about staying in the groove was going on, and we decided to sail with our eyes closed, or at least having the helmsperson sail with her eyes closed, and ears open, to feel the groove by sound alone.
You see, the boat makes a different noise when sailing close hauled at a tight angle to the waves. The waves are generally perpendicular to the wind, so there is a distinctive sound as the bow crests each wave and drops into the next trough. There wasn't much in the way of waves, but just enough to hear this particular frequency.
So we started to sail a wavy course. We'd shine the flashlight up at the mast head to calibrate how close the windex said we were, to what the groove felt like, then she'd close her eyes and continue for about a minute on course, then slowly turn down about 5 degrees, listen to the change in the timber of the sound of the boat going through the water, feel the change with a little sideways roll combining with the pitching motion to create a wallow.
We would then head back up to get in the groove. We did this about five times then sailed up a little closer and held that all the way to the north side of the Circle. At that point, it wasn't necessary for her to close her eyes, the sound the boat was making was part of the feel. The moonlight on the waves made for a great reference to that lovely shhhh . . . . shhhh . . . . shhhh sound.
It was a magical sail.
No comments:
Post a Comment